<p>MySQL raises ER_BASE64_DECODE_ERROR (code 1575) when it fails to decode a supplied base64 string.</p>
<p>MySQL Error 1575 ER_BASE64_DECODE_ERROR means the server could not decode the given base64 text. Verify the string uses valid base64 characters, strip line breaks, and call FROM_BASE64 or DECODE only on properly encoded data to resolve the issue.</p>
Decoding of base64 string failed
MySQL throws ER_BASE64_DECODE_ERROR with code 1575 and SQLSTATE HY000 when the server tries to convert a base64 string but the input violates base64 encoding rules.
The error appears in SELECT, INSERT, UPDATE, or procedural statements that invoke FROM_BASE64, DECODE, or functions that internally decode base64 data.
Fixing the problem quickly is important because the query stops, stored procedures abort, and downstream applications may see empty result sets or aborted transactions.
Invalid characters such as spaces, tabs, or UTF-8 multibyte symbols inside the base64 text break the decoder.
Mismatched padding with = or missing bytes causes the decode routine to fail and raise the error.
Accidentally double-encoding data or passing a HEX string to FROM_BASE64 also triggers error 1575.
Start by validating that the input contains only A-Z, a-z, 0-9, +, /, and optional = for padding. Any other symbol must be removed or escaped.
If the string comes from client code, confirm it is encoded exactly once and sent in the correct character set (usually utf8mb4).
Use MySQLs TO_BASE64 to generate trusted examples, compare lengths, and adjust padding so the length is a multiple of four characters.
REST APIs sometimes insert line breaks into long base64 payloads. Strip CR or LF characters before calling FROM_BASE64.
Binary columns stored as base64 in JSON may lose padding when truncated. Re-encode with correct = signs.
Legacy tables might mix HEX and base64. Detect format by length and leading 0x and route data to the right decoder.
Always store binary data as BLOB and let MySQL manage encoding instead of embedding base64 in text columns.
Validate inbound strings with REGEXP '^[A-Za-z0-9+/]+={0,2}$' before attempting FROM_BASE64.
Use prepared statements in Galaxy or any SQL editor to separate data from code and prevent accidental encoding changes.
Error 1366 incorrect_string_value occurs when character set conversion fails; verify encoding just like base64 validation.
Error 3140 JSON document invalid can appear if corrupted base64 lives inside JSON. Clean input before INSERT.
Any byte outside the standard 64-character alphabet, including spaces or punctuation, stops the decoder and raises error 1575.
Base64 strings must end with zero, one, or two = signs so the total length is a multiple of four. Missing or extra padding triggers the error.
Passing text that has already been decoded or was encoded twice produces unreadable data and causes MySQL to fail during decoding.
Raised when character set conversion fails. Check client encoding and use proper COLLATE clauses.
Appears when JSON text is malformed, often due to corrupt base64 inside JSON values.
Occurs when the actual length of data does not match column definition, sometimes linked to failed base64 conversions.
No. MySQL only checks format when you call FROM_BASE64 or functions that decode internally.
You cannot disable it, but you can prevent it by sanitizing input before decoding.
Run a REGEXP query to flag rows that contain characters outside the base64 alphabet.
Galaxy highlights errors inline, suggests FROM_BASE64 usage, and lets teams share corrected queries so others avoid the same mistake.
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